Authenticator supplicant construct ptk construct gtk

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also leads to the mutual authentication of the two. Authenticator Supplicant Construct PTK Construct GTK SNonce, MIC GTK, MIC ACK ANonce Fig. 5. Four-way handshake. Copyright © 2010. World Scientific Publishing Company. All rights reserved. May not be reproduced in any form without permission from the publisher, except fair uses permitted under U.S. or applicable copyright law. EBSCO Publishing : eBook Collection (EBSCOhost) - printed on 2/16/2016 3:46 AM via CGC-GROUP OF COLLEGES (GHARUAN) AN: 340572 ; Beyah, Raheem, Corbett, Cherita, McNair, Janise.; Security in Ad Hoc and Sensor Networks Account: ns224671
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20 A. Naveed and S. Kanhere 6.2. Confidentiality and Origin Authentication IEEE 802.11i provides two methods for the security services of data confidentiality and origin authentication . First method, Temporal Key Integrity Protocol (TKIP) is the enhanced version of Wired Equivalent Privacy (WEP) and has been provided for backward compatibility with the hardware that was designed to use WEP. RC4 encryption is used in TKIP. We do not discuss TKIP here, interested readers are referred to the Section 8.3.2 of the standard 4 for further details. Increment PN Construct CCMP Header || Construct AAD Encryption CCM Construct Nonce Encrypted data, MIC Data A2, Priority MAC Header KeyID PN TK Plain text Mpdu Fig. 6. CCMP encryption process and encrypted frame generation. The second method is the Counter mode (CTR) with CBC-MAC Pro- tocol (CCMP). CCMP is based on the Counter mode With CBC-MAC (CCM) 10 of the AES encryption algorithm. CCM combines Counter (CTR) for confidentiality and the Cipher Block Chaining (CBC) Message Authen- tication Code (MAC) for origin authentication. CCM encryption takes four inputs, as shown in Figure 6: the Encryption key, Additional Authentica- tion Data (AAD), a unique Nonce for every frame and the Plain text. CCM requires a fresh temporal key (TK) for encryption in every session. AAD is constructed from the MAC header and consists of the following fields: Frame Control field FC (Certain bits masked), Address A1, Address A2, Address A3, Sequence Control field SC (Certain bits masked), Address A4 (If present in the MAC header) and Quality of service Control field QC (if present). CCMP uses the A2 and the priority fields of MAC header along with a 48-bit Packet Number (PN) to generate the unique nonce value for each frame protected by a given TK. PN is incremented for each MAC Protocol Data Unit (MPDU) resulting in a fresh value of nonce for each Copyright © 2010. World Scientific Publishing Company. All rights reserved. May not be reproduced in any form without permission from the publisher, except fair uses permitted under U.S. or applicable copyright law. EBSCO Publishing : eBook Collection (EBSCOhost) - printed on 2/16/2016 3:46 AM via CGC-GROUP OF COLLEGES (GHARUAN) AN: 340572 ; Beyah, Raheem, Corbett, Cherita, McNair, Janise.; Security in Ad Hoc and Sensor Networks Account: ns224671
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Authentication and Confidentiality in Wireless Ad Hoc Networks 21 MPDU. The output of the encryption is the cipher text and the Message Integrity Code (MIC). The frame to be transmitted is constructed by con- catenating the MPDU header, CCMP header, cipher text and MIC. CCM
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